Apparatus for continuously coating wire



Nmr. 28, 1950 F. c. ELDER ET AL 2,531,561!

APPARATUS FORCONTINUOUSLY COATING WIRE Filed Feb. 18, 1948 2Sheets-Sheet 1 Nov. 28, 1950 F. c. ELDER ET AL 2,531,551

APPARATUS FOR con'rmuousu comma WIRE Filed Feb. 18, 1948 2 Sheets-Sheet2 Patented Nov. 28, 1950 APPARATUS FOR CONTINUOUSLY COATING wms Flint C.Elder and William H. Johns, Cleveland Heights, Ohio, assignors to TheAmerican Steel and Wire Company of New Jersey, a corporation ofNew'Jeraey Application February 1a, 1948, Serial No. 9,038

Claims. 1

This invention relates to c ating by. extrusion processes of wire withcoatings of variousmaterials such as enamels, resin, lacquers or otherplastic materials, and more particularly to guide means for holding thewire concentrically oi the extrusion die while the coating material isapplied at high speeds.

, the wire drawing machine 2 which contains a It is desirable in coatingwirewith such coat- 4 ings to do so in conjunction with the regular wireprocessing apparatus to eliminate extra handling. However, in the caseof final gages of wire the speed of delivery of the wire drawingmachines is in the order of 1000 to 2000 feet per minute or higher whichhas heretofore involved difliculties with the means for guiding the wirethrough the extrusion die. The wire as it comes from the drawing machinehas a slight deposit of lubricating and other foreign material thereonwhich is diflicult to completely remove at such high speeds. Thismaterial tends to come loose from the wire in the guiding means andtends to collect therein. This results in the interior of the guidemeans becoming so small that passage of the wire therethrough is atfirst interfered with and finally results in breakage of the wire.

It is accordingly an object of the present invention to provideapparatus for coating wire which is suitable for use in conjunction witha high speed drawing machine.-

It is a further object to provide a guide for an extrusion die whichpermits coating uncleaned wire at high speeds and at the same timeclosely guides the same into the extrusion die.

The foregoing and further objects will become 2.

apparent from the following specification when read in conjunction withthe attached drawings, wherein:

Figure 1 is a schematic view of apparatus embodying the teaching of ourinvention;

Figure 2 is a plan of the extrusion press;

Figure 3 is a vertical view. partly in section, of the extrusion head;

Figure 4 is .a vertical section of the extrusion die;

Figure 5 is a section on line V-V of Figure 4; and

Figure 6 is a section on line VI-VI of Fig-' ure 4.

Referring more particularly to the drawings, the numeral 2 designates aconventional wire drawing machine wherein a wire W is drawn from a reel4 through a plurality of reducing dies including an exit die 6 whichdetermines a final bath of suitable lubricant and the exit die 6 by apull-out block 8. In accordance with the teachings of our invention, thewire is led from the pull-out block 8 through a heater [0, through anextrusion die l2, a quenching tank l4 onto a takeup spool Hi. If desiredthe coated wire may be coiled on a block mounted on the same spindle asthe pull-out block 8 and having the same diameter. The take-up spool i6is driven by a belt l8 which is driven by the pull-out block 0. Due tothe engagement of the belt I8 with the spool IS, the wire is maintainedat a desired tension in its passage from the pull-out block through theextrusion die 12 and quenching tank l4. Suitable free running sheaves 20are provided to guide the wire through the heater ill, the extrusion diel2, the quench tank l4 and back through the spool I6. I

The extrusion die l2 of our invention is mounted in a head 22 to whichhead plastic under suitable pressure is delivered from a hopper 24through an extruder barrel 26. The extrusion die comprises aholdingmember having a die opening 32 at its lower end and a cylindricalpassage 34 therethrough. Suitable passages 36 are provided adjacent thelower end of the holding member for the passage of the coating materialto the die opening 32. The holding member is mounted in the extrusionhead by means of screw threads 38 at its upper end and extends throughthe extrusion head a short distance. A pin member 40 is disposed in theholder 30 and has a flange 42 adjacent its upper end which engages theupper end of the holder 32 to properly position the lower end of the pinmember relative to the die opening. The lower end of the pin member is aseparate tip portion 44 which is screw threadedly attached thereto. Abore 46 extends through the holder 30 and its tip 44.

A guide member 50 comprising a short portion of tubing is disposed inthe bore of the tip and is held therein by a flange 52 engaging theupper end of the tip. The guide extends forwardly from the tip 44 intothe die opening 32 when the pin member 40 is properly disposed in theholder 30 and held therein by sleeve nut 54. The inner diameter of thetubular guide member 50 is suitably about .006" greater than thediameter of the wire to be drawn therethrough but at any rate theclearance should be no more than .01" for ".010" diameter wire. Thus, itis seen that the wire is closely guided in its passage through the dieopening 32.

gage of the wire. The wire is drawn through 56 A suitable passage 56 isprovided for carrying the plastic material from the barrel 28 to theannular space 58 between the holder 30 and the extrusion head 22 fromwhich it is fed through the bores 36 into the space between the tip 44and the forward end of the holder 30. Thus, it is seen that the amountof plastic extruded on the wire will depend on the correlation betweenthe pressure at which the plastic is fed to the die opening and thespeed of the wire as it is drawn therethrough, The plastic due to itsheated and fluid condition tends to form a small globule around the wireas it emerges from the die as indicated at 60. However this quicklsolidifies and forms a tight covering on the wire.

the speed of the wire which must be therefore closely controlled if auniform coating is to be obtained. Since the wire is withdrawn at auniform speed from the wire drawing machine, it is seen that thisprovides means for closely controlling the speed of the wire as itpasses through the extrusion die.

As a result of the use of the short tubular guide 50, it is notnecessary to clean the wire as it comes from the wire drawing machine.The length of this guide should be between 10 and 100 times the diameterof the wire but not greater than 1". The use of such a short guide ispermitted by having the tip 44 of the pin holder separate from the bodyof the pin holder. Thus by mounting the tip 44 with a screw-threadedconnection, it is possible to have a short guide member and at the sametime securely hold the same from being drawn therethrough by frictionalengagement with the wire.

In operation, wire W from the reel 4 is drawn through the wire drawingmachine 2 and exit guide 6 by the pull-out block 8. In order to enablethe block 8 to pull the wire through the wire drawing machine, the wireis preferably wound around the pull-out block one or two convolutions.The wire then passes through the heater III which dries any moistureremaining on the wire from the liquid lubricant used in the wire drawingmachine. If desired the wire may be heated to a temperature which willbe high enough when the wire reaches the extruding die to maintain thecoating material at the exit end of the extruding die in a fluid statelong enough to facilitate the free flow of the plastic into the tubularform in which it is applied to the wire. The temperature of the wire atthe extruding die may preferably be substantially the same as thetemperature of the coating material whenin the fluid state. The wire isthen drawn through the extrusion die [2, quench tank l4 and onto thespool l6 by the belt l8 which frictionally engages the wire as it iswrapped on the spool. From this it is seen that the wire is coated inconnection with the regular wire drawing operation and in the conditionin which it is delivered from the wire drawing machine. This is possibledue to the special guide member of our invention. It is therefore notnecessary to clean the wire in order to obtain a closely controlledconcentric coating thereon. Such cleaning has heretofore involved aseparate operation since the wire cannot be cleaned at the speed of 1000to 2000 feet per minute or more at which it is delivered from the wiredrawing machine in the case of the finer gages which it is desired to becoated.

While we have shown and described one speciflc embodiment of ourinvention, it will be understood that this embodiment is merely for thepurpose of illustration and description and that The thickness of thiscovering will however vary dependent upon various other forms may bedevised within the scope of our invention, as defined in the appendedclaims.

We claim:

1. Apparatus for applying a plastic coating to rapidly moving, tensionedwire comprising an extrusion die adapted to surround the said movingwire, a guide tube in said die for guiding the wire therethrough, saidguide being less than 1" in length and extending to the exit end of saiddie.

2. Apparatus for applying a plastic coating to rapidly moving, tensionedwire comprising an extrusion die adapted to surround the said movingwire, a tubular guide in said die for guiding the wire therethrough, thelength of said guide being between. 10 and 100 times the diameter of thewire drawn therethrough but not greater than 1" and extending to theexit end of the extrusion die and means for heating the wire prior toits passage through the extrusion die.

3. Apparatus for applying a, plastic coating to rapidly moving,tensioned wire comprising an extrusion die assembly, a holding member insaid die assembly, said member having a bore therethrough terminating ina die opening at the lower end thereof, a pin member mounted in the boreof said holding member, said pin member comprising a tubular body memberhaving a flange at its upper end adapted to engage the upper end of saidholding member, a tip removably mounted on the lower end of said tubularbody member, said tip having a bore therethrough in alignment with theaxis of said tubular body member, a guide tube mounted in said tipextending into the exit end of said die opening, said tube having aflange on its upper end adapted to engage the upper end of said tip toprevent the guide being drawn through said tip, the length of said tubebeing between 10 and 100 times the diameter of wire drawn therethroughbut not greater than 1.

4. An extrusion die assembly for coating wire with plastic material atspeeds in excess of 600 feet per minute comprising an extrusion head, aholding member mounted in said head, said member having a boretherethrough terminating in a die opening at the lower end thereof, apin member mounted in the bore of said holder, said pin membercomprising a tubular body member having a flange at its upper endadapted to engage the upper end of said holder, a tip removably mountedon the lower end of said tubular body member, said tip having a boretherethrough in alignment with the axis of said tubular body member anda guide tube secured in said tip extending therefrom into the exit endof said die opening.

5. An extrusion die assembly for coating wire with plastic material atspeeds in excess of 600 feet per minute comprising an extrusion head, aholding member mounted in said head, said member having a boretherethrough terminating in a die opening at the lower end thereof, apin member mounted in the bore of said holder, said pin membercomprising a tubular body member having a flange at its upper endadapted to engage the upper end of said holder, a tip removably mountedon the lower end of said tubular body member, said tip having a boretherethrough in alignment with the axis of said tubular body member, aguide tube mounted in said tip extending into the exit end of said dieopening, said tube having a flange on its upper end adapted to engagethe upper end of said tip to prevent the guide being drawn through saidtip.

\ FLINT C. ELDER.

WILLIAM H. JOHNS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PA'I'E'N'1- Number Name Date Dimmick Aug. 13, 1935 BoyleJan. 2, 1940 1 Morgan Nov. 18, 1941 MacGregor et a1. Feb. 15, 1944 HeathJan. 2, 1945 Wilson et a1 Apr. 19, 1949 Ingmanson May 31, 1949

